// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_QUIC_CRYPTO_QUIC_SERVER_INFO_H_
#define NET_QUIC_CRYPTO_QUIC_SERVER_INFO_H_

#include <string>
#include <vector>

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/time/time.h"
#include "net/base/completion_callback.h"
#include "net/base/net_export.h"
#include "net/quic/quic_server_id.h"

namespace net {

class X509Certificate;

// QuicServerInfo is an interface for fetching information about a QUIC server.
// This information may be stored on disk so does not include keys or other
// sensitive information. Primarily it's intended for caching the QUIC server's
// crypto config.
class NET_EXPORT_PRIVATE QuicServerInfo {
public:
    explicit QuicServerInfo(const QuicServerId& server_id);
    virtual ~QuicServerInfo();

    // Start will commence the lookup. This must be called before any other
    // methods. By opportunistically calling this early, it may be possible to
    // overlap this object's lookup and reduce latency.
    virtual void Start() = 0;

    // WaitForDataReady returns OK if the fetch of the requested data has
    // completed. Otherwise it returns ERR_IO_PENDING and will call |callback| on
    // the current thread when ready.
    //
    // Only a single callback can be outstanding at a given time and, in the
    // event that WaitForDataReady returns OK, it's the caller's responsibility
    // to delete |callback|.
    //
    // |callback| may be NULL, in which case ERR_IO_PENDING may still be returned
    // but, obviously, a callback will never be made.
    virtual int WaitForDataReady(const CompletionCallback& callback) = 0;

    // Reset's WaitForDataReady callback. This method shouldn't have any side
    // effects (could be called even if HttpCache doesn't exist).
    virtual void ResetWaitForDataReadyCallback() = 0;

    // Cancel's WaitForDataReady callback. |callback| passed in WaitForDataReady
    // will not be called.
    virtual void CancelWaitForDataReadyCallback() = 0;

    // Returns true if data is loaded from disk cache and ready (WaitForDataReady
    // doesn't have a pending callback).
    virtual bool IsDataReady() = 0;

    // Returns true if the object is ready to persist data, in other words, if
    // data is loaded from disk cache and ready and there are no pending writes.
    virtual bool IsReadyToPersist() = 0;

    // Persist allows for the server information to be updated for future users.
    // This is a fire and forget operation: the caller may drop its reference
    // from this object and the store operation will still complete. This can
    // only be called once WaitForDataReady has returned OK or called its
    // callback.
    virtual void Persist() = 0;

    // Called whenever an external cache reuses quic server config.
    virtual void OnExternalCacheHit() = 0;

    struct State {
        State();
        ~State();

        void Clear();

        // This class matches QuicClientCryptoConfig::CachedState.
        std::string server_config; // A serialized handshake message.
        std::string source_address_token; // An opaque proof of IP ownership.
        std::string cert_sct; // Signed timestamp of the leaf cert.
        std::string chlo_hash; // Hash of the CHLO message.
        std::vector<std::string> certs; // A list of certificates in leaf-first
            // order.
        std::string server_config_sig; // A signature of |server_config_|.

    private:
        DISALLOW_COPY_AND_ASSIGN(State);
    };

    // Once the data is ready, it can be read using the following members. These
    // members can then be updated before calling |Persist|.
    const State& state() const;
    State* mutable_state();

    base::TimeTicks wait_for_data_start_time() const
    {
        return wait_for_data_start_time_;
    }

    base::TimeTicks wait_for_data_end_time() const
    {
        return wait_for_data_end_time_;
    }

protected:
    // Parse parses pickled data and fills out the public member fields of this
    // object. It returns true iff the parse was successful. The public member
    // fields will be set to something sane in any case.
    bool Parse(const std::string& data);
    std::string Serialize();

    State state_;

    // Time when WaitForDataReady was called and when it has finished.
    base::TimeTicks wait_for_data_start_time_;
    base::TimeTicks wait_for_data_end_time_;

    // This is the QUIC server (hostname, port, is_https, privacy_mode) tuple for
    // which we restore the crypto_config.
    const QuicServerId server_id_;

private:
    // ParseInner is a helper function for Parse.
    bool ParseInner(const std::string& data);

    // SerializeInner is a helper function for Serialize.
    std::string SerializeInner() const;

    DISALLOW_COPY_AND_ASSIGN(QuicServerInfo);
};

class NET_EXPORT_PRIVATE QuicServerInfoFactory {
public:
    QuicServerInfoFactory() { }
    virtual ~QuicServerInfoFactory();

    // GetForServer returns a fresh, allocated QuicServerInfo for the given
    // |server_id| or NULL on failure.
    virtual QuicServerInfo* GetForServer(const QuicServerId& server_id) = 0;

private:
    DISALLOW_COPY_AND_ASSIGN(QuicServerInfoFactory);
};

} // namespace net

#endif // NET_QUIC_CRYPTO_QUIC_SERVER_INFO_H_
